The Nord Express was part of the Compagnie Internationale des Wagons-Lits, and ran regularly between Paris and St Petersburg until the First World War, when it was diverted to Warsaw. After World War II the term Nord Express defined the journey from Paris to Copenhagen, and nowadays only links Paris and Hamburg.

American explorer Robert Edwin Peary's claim in 1909 to have been the first person to reach the North Pole was disputed soon after it was made, possibly as a result of a navigational miscalculation. In 2005 Briton Tom Avery and four companions recreated Peary's journey with dogsleds.

The bass Fyodor Chaliapin (1873-1938) was arguably the most famous Russian opera singer of the 20th century.

Born into a peasant family in Kazan, he sang at New York's Met and debuted in London and Paris in 1921, thanks to an introduction from Sergei Diaghilev in 1921. Although Chaliapin sang most major opera roles, it was the folkloric Song of the Volga Boatmen that earned him worldwide fame.

He knew the Nabokovs and is said to have sung at their house on 47 Bolshaya Morskaya Street.

French aviator Louis Blériot, (1872-1936) became an instant celebrity when he crossed the English Channel in 37 minutes in July 1909. His crossing was the first by a man over a large body of water in a heavier-than-air craft, and Blériot beat two others for the £1000 prize offered by London's Daily Mail newspaper.

Page 114.
" It was at night, however, that the Compagnie Internationale des Wagons-Lits et des Grands Express Europeens lived up to the magic of its name "

The Compagnie Internationale des Wagons-Lits (et desGrands Express Européens) the iconic symbol of which was the letters "WL" held up by two lions, was founded in Belgium in 1872 by Belgian Georges Nagelmackers. It was the main provider of railway sleepers and dining cars in the late 19th and early 20th century, and it introduced the Orient Express, Nord Express and Sud Express services.

Samuel Lusker McCroskey (1893-1960) was a Brigadier General in the U.S. Army. Nabokov is most probably referring here to McCroskey's appointment in 1945 as Commandant of the Biarritz American University, when he occupied the Royal Suite of the Hotel du Palais.

Opened in summer 1945 by the US War Department as a post-war morale booster, to provide a university education to US military personnel awaiting redeployment or a return to civilian life, the university had 4000 places and took over the entire town of Biarritz. The town's casino was converted to the university library, and accommodation for 'students' was found in 40 luxurious hotels and nearly 100 villas where the rich of Europe had previously come to spend winters. Teachers were academics brought over from American universities and colleges as well as actors or artists, including singer Marlene Dietrich who taught drama.

Another American university - also up and running within 60 days of V E Day - was set up in Europe, in Shrivenham, UK as the SAU (Shrivenham American University). The British Army's Military College of Science now occupies the old SAU premises.

Both universities were closed in March 1946, having provided a short education for approximately 18 000 American soldiers. A street sign in Biarritz, "Rue de l' Université Americaine, 1945-1946" still bears witness to the educational experiment.

After retiring from the army, McCroskey joined Douglas Aircraft where he worked on the development of the Nike and Hercules missiles.

Page 115.
" which stands on the site of a former palace, where, in the sixties, that incredibly agile medium, Daniel Home, is said to have been caught stroking with his bare foot (in imitation of a ghost hand), the kind, trustful face of Empress Eugenie "

Daniel Home (pronounced 'Hume') (1833-1886) was a well-known Scottish medium, fêted all over Europe and America for his alleged ability to levitate and to communicate with the dead in séances. The reference to Empress Eugenie here is possibly to do with the invitation to the Tuileries to perform a séance by her husband Napoleon III.

Page 123.
" under the windows of which, in a roped-off section of the square, a huge custard-coloured balloon was being inflated by Sigismond Lejoyeux, a local aeronaut "

After several mentions of real celebrities of the era,"Sigismond Lejoyeux" is a typically Nabokovian insertion, a pun on Sigmund Freud's name. Nabokov even explained the pun himself in his 1967 Foreword to Speak, Memory:"Reviewers read the first version more carelessly than they will this new edition: only one of them noticed my “vicious snap” at Freud in the first paragraph of Chapter Eight, section 2"